Star Trek is a science fiction television series created by Gene Roddenberry in 1966 that tells the tale of the crew of several starships in the federation and of their adventures "to boldly go where no man has gone before." The original show was cancelled in 1969, but fans refused to let it die. To date, four additional TV series and ten motion pictures set within the Star Trek universe have been released. Today, it is rare for a person not to have heard of Star Trek. It is one of the two pillars (with the later franchise Star Wars) of late twentieth century science fiction.

Initially, Star Trek (often abbreviated TOS for "The Original Series") did not meet with much success. However, after the original series was canceled it turned out that Star Trek had very devoted and active fans. The fans, calling themselves Trekkies, made reruns of the show popular and created a market for later series and movies based on Roddenberry's work. The stories of Star Trek are now a recognized part of American culture, and are gaining in international popularity as well. Partly due to lobbying from fans of the series, NASA agreed to name its prototype space shuttle the Enterprise.

Many episodes of the first series involved an encounter with a power much greater than that of the ship and its crew. These powers took many forms: advanced alien races with psychic powers; rogue alien machines; and even, in one case, a god. Sometimes a member of the ship's crew would acquire godlike powers in some freak accident, almost invariably bringing doom upon themselves or the crew. A cautious attitude towards automation prevailed; in many episodes, Captain James T. Kirk (William Shatner) freed alien cultures from repression by dictatorial computers.

Most situations of this type were resolved when the power in question came close to enslaving (or destroying) the ship and crew, only to be saved by Kirk. His usual strategy was to outwit the "enemy" with a deus ex machina, often accompanied by an impassioned appeal to humanistic values.

Outstanding episodes of the Original Series include "The Menagerie" (the original show's only two-part episode, written by Gene Roddenberry and partially derived from the unused pilot "The Cage"), "The Trouble with Tribbles" (written by David Gerrold), "The City on the Edge of Forever" (written by Harlan Ellison), The Devil in the Dark and "Balance of Terror." While most episodes of TOS were self-contained, there were several notable themes that wove themselves throughout the entire series. Arguably, the most important was the way that Star Trek explored, confronted, and questioned the major issues on American minds in the 60's, like sexism, racism, nationalism, war, and peace. Roddenberry believed that if people were shown new perspectives on these issues, they would view those issues differently in their everyday lives.

Star Trek: The Next Generation added a lot more background information about the Federation, a diverse union of starfaring cultures centered on Earth. The Federation does not use money; it is dominated by the economic condition known as abundance, enabled by advanced replicator technology.

Abundance, or lack of scarcity, means that everyone can satisfy all of his material needs and wants. Working, buying and selling is not necessary; therefore money is (arguably) obsolete.

In the Federation, unpleasant emotions such as greed or jealousy are greatly reduced, since possessions no longer have any value beyond that of sentiment. Characters, especially Captain Jean-Luc Picard, often expound upon how people of the Federation now strive only to better themselves and their fellow man, often in response to a question like "But what do you do all day?".

Many episodes and films revolve around a threat to the status quo that is resolved by the crew, and usually everything is back to normal by the closing credits. This plot device is popularly known as the "reset button." The device is a common bane of serialised programs, and by the time of the end of Voyager and Deep Space Nine the writers had mostly switched to the "story arc" model.

Roddenberry was an ardent proponent of egalitarian politics, and frequently used the shows to showcase his vision of a future society based on those principles. The original series had a prominent African-American female crew member, Nyota Uhura (Nichelle Nichols). Nichols was one of the first African-American women to hold any major acting role on American television. Only 21 years after the bombs fell on Hiroshima and Nagasaki, Star Trek had a Japanese officer, Hikaru Sulu (George Takei). In the second season, perhaps in response to Soviet complaints that the "international" crew contained no Soviets, a Russian character, Pavel Chekov (Walter Koenig) was added.

The Vulcan first officer Mr. Spock (Leonard Nimoy), was at first rejected by network officials who feared that his vaguely satanic appearance might prove too disquieting. However, Mr. Spock went on to become one of the most popular characters on the show, arguably due to his role as the peaceful, logical, calm foil to Doctor McCoy's impassioned, old-fashioned, fiery personality.

Modern viewers might find the old series' portrayals of minorities and women backward, but the program was progressive and daring for its time. One of Star Trek's claims to fame is that it featured the first televised kiss between a European-American and an African-American in the United States. In an episode that used mind control as a ruse to break this taboo, Captain Kirk and Uhura were forced to share the first interracial kiss on American TV (episode #67 "Plato's Stepchildren"). The series also showed a very powerful alien species, the Klingons, as resembling Earth Asians rather than powerful white Europeans. Opinions are divided on whether this was a reference to Red China, or an attempt to maintain a balanced view of ethnicity.

Star Trek: The Animated Series is an animated TV show set in the fictional Star Trek universe. The official name of the series was simply Star Trek, but the designator "The Animated Series" is added by fans to differentiate it from the original Star Trek (or Star Trek: The Original Series).

It was produced by Filmation and ran for two seasons 1972-1973, airing a total of twenty-two thirty-minute episodes. This show featured most of the original cast performing the voices for their characters, except for Pavel Chekov (Walter Koenig), who was replaced by Lieutenant Arex. Arex was a member of a tripodal species which had three arms and three legs.

While it was hoped Star Trek could take full use of the freedom that animation provided, budget restraints were still a concern, and the animation quality was poor. However, it did afford the crew a set of much more encompassing alien landscapes than could be provided by a small studio.

Noted science fiction authors such as David Gerrold and Larry Niven contributed scripts for the animated series. In addition to a sequel to the famous episode The Trouble with Tribbles, two notable episodes of the cartoon include Yesteryear (a time-travel episode in which Mr. Spock uses the time gateway from the live-action episode City on the Edge of Forever to travel to his own childhood past) and Niven's The Slaver Weapon (adapted from his own short story "The Soft Weapon"). Larry Niven in particular included some elements from his Known Space mythos, such as the Kzinti and the Slavers.

It is of note that the Enterprise ship in this series, while theoretically the same ship on the live action program, had a holodeck just like was introduced on Star Trek The Next Generation.

In 1987 a new series launched, Star Trek: The Next Generation (abbreviated ST:TNG or TNG), which featured a new crew and a new plotline. In contrast to the original series, the crew of the USS Enterprise NCC 1701-D tended to have encounters with other races that were technologically equal in nature. A considerable number of the episodes involved "non-encounter" related plotlines such as temporal loops, character dramas, and various natural disasters.

While there were several encounters with advanced races, the crew of the Enterprise was less inclined to be tricky and hostile, favoring peaceful negotiation. In some cases, encounters were resolved in an entirely humorous way.

A major change was the more dedicated observation of the Prime Directive, which states that the advanced Federation shouldn't interfere with the technological or moral development of other cultures. This was often used as a plot device to create moral conflict within characters, when they saw races in need of help that they were legally bound to ignore.

However, the most noticeable difference between TOS and TNG was that the series had strong historical ties between episodes. Items, enemies, and characters from previous episodes and seasons often reappeared, giving the series a much stronger sense of continuity. There was a major recurring character, Q, established in the first episode, "Encounter at Farpoint." He was the most influential single enemy of the entire series, and had been planned that way.

Roddenberry continued to be credited as executive producer of Star Trek: The Next Generation, but his influence lessened as the series progressed. With the addition of producer Rick Berman, the series slowly took on a more active nature and came to rely more and more on action and warfare. This became evident in later episodes of TNG, and was the basis of the ongoing plotlines of most of the following episodes.

In 1993, Paramount Pictures launched Star Trek: Deep Space Nine (also called DS9), which ran concurrently with The Next Generation for several years and continued after TNG ended. DS9 was a departure from the established Star Trek formula, in that it was the first series not to feature the Enterprise and its crew. Instead the series chronicled the events surrounding Deep Space Nine, a remote Federation outpost on a former Cardassian mining station, near a wormhole to the Gamma Quadrant.

Deep Space Nine left behind some of the utopian themes that embodied the previous versions of Star Trek, focusing more on war, political compromise, and other modern-day themes. Commander Benjamin Sisko (Avery Brooks) was forced to work with a fractured Bajoran government, with his first officer, Major Kira (Nana Visitor) being a former underground resistance leader who initially did not welcome the Federation's assistance in running the station.

The episode "Rules of Acquisition" almost casually introduced the Dominion, an alliance of planets in the Gamma Quadrant headed by the Founders. The Dominion eventually went to war with the Federation, the Romulans and the Cardassians, in a story arc taking up most of the final two seasons of the show. Another example of DS9's darker, more controversial plot material is Section 31, a secret police division in Starfleet Intelligence. This undemocratic shadow organization justifies its unlawful, ethically questionable tactics by claiming that it is essential to the continued existence of the Federation. Section 31 is prominent in several episodes of the Dominion War plot arc.

Star Trek: Voyager first aired in 1995, right after The Next Generation concluded. It was set in the same time period as Deep Space Nine, but on a ship again—the USS Voyager. In the pilot episode, Voyager is sent on a mission to locate a ship piloted by a cell of the Maquis, an anti-Cardassian terrorist organization. During a chase through the Badlands, the ships are transported to the other side of the galaxy by an ancient alien device. The two crews are forced to integrate after the Maquis ship is destroyed by Kazon raiders.

Although the conflict between the freedom-loving Maquis and the establishment Federation crew was explored in the first two seasons, the series concentrated on the exploration of the Delta quadrant during the Voyager's long trek home. On the way, the aptly-named vessel had to contend with organ-snatching Vidiians, the nightmare legions of the Borg, and the extradimensional horrors of Species 8472.

In 2001, the newest series began, initially entitled Enterprise. Enterprise was set in 2151, ten years before the founding of the Federation. It was the first series without "Star Trek" in the title. It also contained more action, more of a focus on the dangers of space exploration with inferior technology, and a "Temporal Cold War" plot arc which seems to lead to a departure from the traditional Star Trek timeline. In the third season the show was renamed Star Trek: Enterprise. A number of fans have voiced strong negative opinions about this latest incarnation of Star Trek, feeling the producers are simply there for the money, focusing on action and scantily clad female aliens instead of the more central themes of prior series. Others have argued that the generally low ratings of the show are a result of the effort to market its host network, UPN, towards a younger male demographic. Enterprise is the lowest rated of the Star Trek series, following a downward trend since The Next Generation.